Review of UFO 31

The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.

Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.

The boat equipped with a masthead rig. The advantage of a masthead rig is its simplicity and the fact that a given sail area - compared with a fractional rig - can be carried lower and thus with less heeling moment.

The boat is typically equipped with an engine.

What is Capsize Screening Formula (CSF)?

The capsize screening value for UFO 31 is 1.99, indicating that this boat could - if evaluated by this formula alone - be accepted to participate in ocean races.

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 6.8 knots. The term "Theoretical Maximum Hull Speed" is widely used even though a boat can sail faster. The term shall be interpreted as above the theoretical speed a great additional power is necessary for a small gain in speed.

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for UFO 31 is about 159 kg/cm, alternatively 895 lbs/inch.
Meaning: if you load 159 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 895 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for UFO 31 is 21.3.

Comparing this ratio with similar sailboats show that it is more comfortable than 34% of all similar sailboat designs. This comfort value is just below average.

What is L/B (Length Beam Ratio)?

The l/b ratio for UFO 31 is 3.08.

Compared with other similar sailboats it is more spacy than 58% of all other designs. It seems that the designer has chosen a slightly more spacy hull design.

What is Displacement Length Ratio?

The DL-ratio for UFO 31 is 217 which categorizes this boat among 'light crusers & offshore racers'.

66% of all similar sailboat designs are categorized as heavier. A light displacement requires less sailarea and has higher accellerations.

What is SA/D (Sail Area Displacement ratio)?

The SA/D for UFO 31 with ISO 8666 reference sail is 15.5, with a 135% genua the SA/D is 18.7.

The SA/D ratio indicates that it is faster than 38% of all similar sailboat designs in light wind.

What is Relative Speed Performance?

The Relative Speed Performance for UFO 31 is 38

The relative speed performance is 38 which means that a it is faster than 38% of all similar sailboat designs.

Dimensions of sail for masthead rig.

Are your sails worn out? You might find your next sail here: Sails for Sale

If you need to renew parts of your running rig and is not quite sure of the dimensions, you may find the estimates computed below useful.

This section shown boat owner's changes, improvements, etc. Here you might find inspiration for your boat.

Do you have changes/improvements you would like to share? Upload a photo and describe what to look for.

We are always looking for new photos. If you can contribute with photos for UFO 31 it would be a great help.

If you have any comments to the review, improvement suggestions, or the like, feel free to contact us. Criticism helps us to improve.

[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.